The invention relates to photography and photographic methods and equipment and more particularly relates to an underwater camera housing having a sealed pivotable shutter actuator and related method.
Some one-time-use cameras are made for use both underwater and out of water. Commonly available single use cameras have a manual shutter release that is pressed to capture a picture. This kind of mechanism is practical and inexpensive, particularly when coupled with a spring operated impact shutter. For underwater use, the camera must seal out water under pressure and the shutter release must not trip as a result of the water pressure itself. With quite shallow water, the latter problem can be solved by biasing a shutter release against the water pressure. This biasing is more than the biasing required to prevent unintentional tripping of the shutter in out of water use. The biasing required increases in the same manner as water pressure and at moderate depths renders the shutter release very cumbersome to use. This is even more problematic when the camera is used out of water.
U.S. Pat. No. 5,126,772 teaches a solution to this problem. A camera housing seals out water. An indent forms a figure eight, defining a shutter actuator in the shape of a pair of joined pads. The indent is a bend in the thin housing that acts as a flexure. Within the flexure, the defined actuator acts like a single lever and pivots about a rib that bridges the neck of the flexure and bears against the underlying frame assembly. The opposed pads counterbalance the effect of water pressure. The flexure is sufficiently resilient so as to remain flexible under water. A protrusion on the underside of one of the pads acts on an inner shutter button when the respective pad is pushed. A shortcoming is that the characteristics of the housing are compromised by many different, often competing constraints: flexibility, resilience, rigidity. Other desirable characteristics, such as toughness for impact resistance and hardness for resistance to cosmetic damage would likewise compete with the other constraints. For the shutter actuator, the constraints are met by varying thickness and shape of a one-piece, single material component. As a result, the camera is less than optimal in one or more areas. The shape and low relief of the shutter button of the housing also presents a risk of temporary confusion during picture taking, since the user must locate the correct one of the two upwardly facing pads and then press down to trip the shutter.
U.S. Pat. No. 5,339,124 teaches another underwater camera assembly. A frame mounted on the top of the camera holds a toggle away from an inner shutter release. The toggle has a pair of opposed pads. The frame and toggle are separate pieces and are separate from a flexible bag that covers the other parts and acts as a water-tight housing. The frame and toggle are relatively large, and thus easily located tactilely, but the user must still identify which of two pads to press down to trip the shutter. The flexible bag does not protect against impacts like a rigid housing and has a risk of tearing.
U.S. Pat. No. 5,508,766 teaches an underwater camera that has shutter actuator in the form of a cantilevered beam that is part of a rigid housing. An inner shutter button of the camera is in contact with a flexible part of the housing under the cantilevered beam. The actuator has the advantage of being large and thus easily locatable tactilely. On the other hand, the flexible part of housing over the inner shutter button is not counterbalanced and thus must be biased against water pressure. The housing provides a one-piece, one material part for the actuator, but that part is subject to competing constraints, in the same manner as U.S. Pat. No. 5,126,772; such as requiring thinness for flexibility in one part and greater thickness for rigidity in another. As a result, the camera is less than optimal in one or more areas.
Two shot injection molding is a well-known technique that provides one-piece plastic castings that are made of different materials in different regions of the casting. The different materials are united by codiffusion of adjoining regions of the two different materials. During molding, conditions are selected such that the molecules of the two different regions diffuse together before solidification. The codiffused zones have interpenetrating polymer networks. (This is also referred to as xe2x80x9cmolecular entanglementxe2x80x9d.)
A variety of two shot molding techniques are known, such as those disclosed in U.S. Pat. Nos. 6,066,282; 4,460,534; 6,296,796; and 5,737,002. Among these techniques is the use of a hard engineering plastic for one of the regions and a tougher, but softer material such as an elastomer, for another region of the casting. EP 0 865 779 A1 discloses an orifice coupling that has an internal, soft wiper seal formed by two shot injection molding. The use of two shot molding for the housing of an underwater one-time-use camera is disclosed in U.S. Pat. No. 5,832,312.
It would thus be desirable to provide improved housings and methods, in which an actuator is counterbalanced and water-tightly sealed and simply produced.
The invention is defined by the claims. The invention, in broader aspects, provides an underwater housing that has a shell having inside and outside surfaces and an opening extending between the surfaces. An actuator is disposed in the opening. The actuator has an outer member disposed external to the opening and an inner member disposed internal to the opening. The actuator has a torsion bar joining the members to the shell. The members are pivotable about an axis through the torsion bar, between an initial orientation and a pivoted orientation. The torsion bar is relaxed when the members are in the initial orientation and tensioned when the members are in the pivoted orientation. A facing is united with the shell and the actuator. The facing seals the opening. It is an advantageous effect of the invention that an improved housings and methods are provided, in which an actuator is counterbalanced and water-tightly sealed and is of one-piece with a housing part.